Presently, it is a most simple, convenient and natural way to use a touch screen, as an input medium, to perform human-machine interaction. Integration of touch function on a liquid crystal display (LCD) or an organic light-emitting diode (OLED) has become a research focus for more and more manufacturers of flat panel displays.
In order to further reduce the size of the touch screen and thus reduce the size of a mobile terminal with the touch screen, in recent years an in cell touch panel (TP) is developed in the field of display, and a touch electrode is integrated inside a liquid crystal display panel for the in cell TP. Therefore, the touch screen using in cell display technique is smaller than the touch screen using one glass solution (OGS) technique.
In the conventional in cell TP, a common electrode in a pixel area doubles as a touch electrode, which can reduce the size of the in cell TP. The common electrode doubling as the touch electrode is arranged below an insulation layer due to the limitation of the structure of film layers, therefore, it is extremely difficult to test the potential of the common electrode in the parsing process. It is hard to use an oscilloscope probe or a probe of a flat panel display (FDP) manual prober to pierce the insulation layer, especially in the case that a pixel electrode is located above the common electrode. In placing the probe it is likely to cause contact between the probe and the pixel electrode, and if the pixel electrode is pierced by using brutal force, it is likely to short-circuit the pixel electrode to the common electrode, thereby affecting a test result.
Therefore, there is a need to provide an array substrate, a touch display apparatus and a test method for the touch display apparatus to reduce the difficulty of testing the potential of the common electrode and improve the accuracy of the test result.